linux-kernel - [PATCH 5.2 071/162] NFSv4: Fix a credential refcount leak in nfs41_check_delegation

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Message-Id: <20190827072740.607306162@linuxfoundation.org>
Date:   Tue, 27 Aug 2019 09:49:59 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.2 071/162] NFSv4: Fix a credential refcount leak in nfs41_check_delegation_stateid

[ Upstream commit 8c39a39e28b86a4021d9be314ce01019bafa5fdc ]

It is unsafe to dereference delegation outside the rcu lock, and in
any case, the refcount is guaranteed held if cred is non-zero.

Signed-off-by: Trond Myklebust <trond.myklebust@...merspace.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/nfs/nfs4proc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 63edda145d1b8..420f2350c2781 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2752,8 +2752,7 @@ static void nfs41_check_delegation_stateid(struct nfs4_state *state)
 	if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
 		nfs_finish_clear_delegation_stateid(state, &stateid);
 
-	if (delegation->cred)
-		put_cred(cred);
+	put_cred(cred);
 }
 
 /**
-- 
2.20.1